“The fast and powerful bluefin tuna is among the most overfished species on Earth. Here, bluefin in an undersea pen in the Mediterranean are fattened for the booming sushi market. These fish were taken from the wild, reducing the potential breeding population.”

See more pictures from the March 2014 feature story “Quicksilver.”

The bluefin tuna is one of the most overfished species on the planet. The boom of the sushi market contributed for the excessive capture of the kind of tuna. Find more about this story at National Geographic march issue.

I hope you have enjoyed today’s National Geographic photo “Penned in“.